Process of manufacturing peroxid of hydrogen.



WALTER WEBER, 0F DUSSELDORF, GERMANY, ASSIGNOR T0 THE FIBM CIE., 0FJD'USSELIDORF, GERMANY.

OF HENKEIQ &

PROCESS OF MANUFACTURING PEROXID OF HYDROGEN.

No Drawing.

To all whom it may concern.

Be it known that I, WALTER WEBER, a citizen of the German Empire, andresiding at Dusseldorf, Germany, have invented a certain new and usefulImproved Process of Manufacturing Peroxid of Hydrogen, of which thefollowing is a specification.

In the copending patent application Serial No. 766,091 of May7, 1913, aprocess of cathodically making peroxid of hydrogen in an electrolytecontaining oxygen or oxygenous gases has been described, in which thesegases have been supplied and the electrolysis itself has been broughtabout at a pressure above atmospheric. In this process amalgamated goldcathodes were used. I have found that besides being very expensive theuse of these gold cathodes is connected with certain disadvantages, andI have succeeded by further experiments in finding that these defectscan be obviated when cath odes of a different kind are employed.

I have found that I can continuously carry into practice the cathodicmanufacture of peroxid of hydrogen, c. e. that I can save there-amalgamation of the cathodes requisite under certain conditions atcertain intervals of time when the expensive cathode of gold amalgam isused, when I employ instead of this expensive cathode of gold amalgam acheaper cathode material, such as silver amalgam, i. c. a compound ofsilver and mercury, or an amalgamated silver.

cathode.

Owing to using the cathode of silver amalgam instead of the cathode ofgold amalgam I materially reduce the cost of the process ofmaking-peroxid of hydrogen and I also obtain a'better yield.

Example: I separate the anode chamber and the cathode chamber in asuitable electrolyte, e. g. the aqueous solution of a mineral acid, by adiaphragm of asbestos from one another and insert an amalgamated silvercathode or a cathode composed of silver I amalgam. I then saturate thiselectrolyte at apressure of 100 atmospheres with oxygen or with a gascontaining oxygen and electrolyze under pressure. It is not necessary toemploy absolutely pure oxygen, since Specification of Letters Patent.

Patented May a, 1915.

Application filed February 26, 1914. Serial No. 821,217.

the desired results may be obtained with a gas containing a smallproportion of oxygen such, for example, as air. When a high currentdensity of, e. 9., 5 'amperes per square centimeter is used I find that2 volts sufiice, as the saturation of. the electrolyte with oxygen underpressure diminishes the voltage of decomposition. The oxygen or thegascontaining oxygen must be both supplied into and distributed ordissolved in the electrolyte under pressure, and care must be taken thatthe electrolyte is always at a pressure materially higher than that ofthe at mosphere. Instead of the mineral acid, 6. g.

sulfuric acid, solutions of alkalis or earth' alkalis or directlyalkaline solutions may be used which contain free'alkali or earthalkali. The result is not so good, however, as when mineral acid isemployed. When less value is attached to the purity of the peroxid ofhydrogen obtained than to high eficiency it is preferable to employstabilizing admixtures, such as boracic acid or urea, which, as isknown, are able to retard the catalytic decomposition of the peroxid ofhydrogen.

I claim a y 1.- A process of making hydrogen peroxid which comprisesreducing oxygen or oxygenous gases. dissolved in a suitable electrolyteto hydrogen peroxid at a cathode com- 1ng oxygen or oxygenous gasesinto'the watery solution of a suitable electrolyte under high pressureand during the simultaneous generation of hydrogen at a cathode composedof silver amalgam by electrolysis.

In testimony whereof, I afiix my signature in. the presence of twowitnesses.

WALTER WEBER. [n s.] Witnesses: A

